In the present study, cyanide tailings were used as raw materials for preparing of iron-carbon micro-electrolytic fillers through coal-based direct reduction process. The fillers were used to treat methyl orange solution. The effects of calcination temperature, calcining time and coal dosage on the degradation of methyl orange were studied. The results showed that the fillers presents the best performance for removing methyl orange, which prepared under the conditions of calcination temperature 1250℃, calcination time 60min and coal dosage 30%. Increasing the amount of filler and reducing the initial pH of the solution facilitates the removal of methyl orange. For the treatment of 400mL methyl orange solution with a concentration of 100mg/L, the removal rate of methyl orange was close to 100% with 2.0g filler under acidic conditions when the treatment time was 30min. XRD analysis showed that the main crystalline phase in the filler prepared under optimal conditions was zero-valent iron. SEM analysis showed that the sizes of the zero-valent iron particles in the filler were all below 50μm, and the zero-valent iron and residual carbon constituted the micro-electrolytic filler.